ALBANY, NY-- The state's top health regulator on Tuesday signaled he would need more time to complete his review of large-scale hydraulic fracturing, but the head of the Department of Environmental Conservation says it may not delay a decision on fracking for long.

State Health Commissioner Nirav Shah wrote in a letter Tuesday that his review of the health impacts of fracking will "require additional time to complete based on the complexity of the issues."

With Shah's review still incomplete, the DEC will not be able to issue a dense, lengthy environmental impact statement on Wednesday -- a requirement if the agency wishes to meet a Feb. 27 deadline for its regulations. If the DEC misses the late-February deadline, it would have to reintroduce the rules and open them to public comment for at least 45 days.

But in a separate statement issued Tuesday, DEC Commissioner Joe Martens indicated his agency would move forward with issuing fracking permits without regulations in place -- if the health review doesn't turn up any major issues.

"If the DOH Public Health Review finds that the (Supplemental Generic Environmental Impact Statement) has adequately addressed health concerns, and I adopt the SGEIS on that basis, DEC can accept and process high-volume hydraulic fracturing permit applications 10 days after issuance of the SGEIS," Martens said. "The regulations simply codify the program requirements."

Shah's review was launched in late September, when he was tasked with determining if the DEC's planned guidelines for fracking are adequate to protect public health.

In his letter to Martens Tuesday, Shah said his team is reviewing three outside, health-related studies that have been underway or are just being launched, including one by the University of Pennsylvania and another by the U.S. Environmental Protection Agency.

He also revealed that he has extended agreements with three academic health consultants who have been assisting with his review. Last week, the three consultants revealed that their work had been completed several weeks ago.

"My team and I will be in Pennsylvania and Washington in the coming days for first-hand briefings on these studies and their progress, which will assist in informing the New York review," Shah wrote in his letter to Martens.